Over the past three months, The Times identified more than 170,000 gun ads on Armslist. Some were for the same guns, making it difficult to calculate just how many guns were actually for sale. Even so, with more than 20,000 ads posted every week, the number is probably in the tens of thousands.

Notably, 94 percent of the ads were posted by "private parties," who, unlike licensed dealers, are not required to conduct background checks.

Armslist makes its agenda clear, leading its front page with quick-links to sales listings for what it calls "Feinstein's Favorites": assault weapons targeted for regulation like AKs, AR-15s, Uzis, and MAC-10s.

The would-be purchasers included Omar Roman-Martinez, a double-felon and convicted domestic abuser who in several posts over more than a week sought a handgun and 9mm ammunition, even offering "to trade a tablet computer or a vintage Pepsi machine for firearms." (When contacted by the paper, he said he'd decided not to buy a piece.)

Then there's the Rhode Island fugitive with two felony warrants who wanted an AK-47; the domestic batterer selling his SKS; and the South Carolinian who's put 80 guns up for sale since February, and told the paper he doesn't do background checks or keep any sales records. The reason: "I can just sort of read people."